1. Field of the Invention
This invention relates to the equipments and systems used to drill small holes in the wall of large diameter well holes, particularly small horizontal holes that are drilled at right angles to the large well hole.
2. Prior Art
There have been several systems designed for the boring of small diameter holes in the wall of a large diameter well hole, but they have mostly been ineffective due to the problems of low rotation speed of drilling with downhole fluid motors or drill pipe because this type of drilling requires large pressure on the drill bit which tends to cause the flexible drill pipes particularly wire wound pipes to fail. There has been electrical powered systems designed but these systems have been very limited in the depth or length of small holes that can be drilled from a well hole. All systems drill pipe, fluid motor or electrical motor also have another limitation in that they are suspended in a well hole by drill pipe and require considerable time in the hoisting of the systems in and out of a well hole that would be required in the drilling of a pattern of small holes all the way around a well hole.